Methods, flash memory controller, and electronic device for SD memory card device

ABSTRACT

A method for controlling data transmission mode of an SD memory card device, which at least operates under an SD mode, includes: sending a first power signal from an electronic device to the SD memory card device via pin VDD1 to control and make the SD memory card device enter an initial state; and, sending a second power signal via one of a pin VDD2 and a pin VDD3 to the SD memory card device, to control and make the SD memory card device enter an Linkup state of a PCIe mode wherein a voltage level of the second power signal is lower than a voltage level of the first power signal.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The invention relates to a mechanism of controlling data transmissionmodes of a memory card device, and more particularly to a method ofcontrolling data transmission modes of a secure digital (SD) memory carddevice and a corresponding electronic device.

2. Description of the Prior Art

Generally speaking, the types of memory card devices designed, producedor sold by different manufacturers on the market are different. Thedifferent memory card devices may respectively comprise differentnumbers of signal pins, and data transmission modes supported by thedifferent memory card devices may be different. Also, the actual voltagevalues of the logic signal levels and voltage values of power supplylevels specified by the input/output communication interface standardsrespectively employed by the different data transmission modes aredifferent. Thus, when a memory card device is connected to a host, thecircuits may be damaged if the data transmission mode of the host isdifferent from that supported by the memory card device.

SUMMARY OF THE INVENTION

Therefore one of the objectives of the invention is to provide a methodfor controlling a data transmission mode of an SD memory card device, acorresponding electronic device, a method used in an SD memory carddevice, and a flash memory controller of an SD memory card device, tosolve the above-mentioned problems of the prior art.

According to an embodiment, a method for controlling a data transmissionmode of an SD memory card device is disclosed. The electronic device isused as a host and has a first external signal port. The SD memory carddevice is capable of operating an SD mode at least and has a secondexternal signal port, and the SD memory card device is coupled to theelectronic device via the first external signal port and the secondexternal signal port. The method comprises: sending a first power signalcorresponding to the SD mode from the electronic device to the SD memorycard device via the first external signal port and a pin VDD1 of thesecond external signal port, to control and make the SD memory carddevice enter an initial state; and sending a second power signal fromthe electronic device to the SD memory card device via one of a pin VDD2and a pin VDD3 of the second external signal port, to control and makethe SD memory card device enter a Linkup state of a PCIe mode, a voltagelevel of the second power signal being lower than a voltage level of thefirst power signal. A plurality of pins, used for a data line, of anUHS-I input/output communication interface standard employed by the SDmode of the SD memory card device are shared by another input/outputcommunication interface standard of a PCIe channel with an NVMe protocolemployed by the PCIe mode, and the plurality of pins of the UHS-Iinput/output communication interface standard employed by the SD modecomprise pins of pin numbers 1, 7, 8, and 9.

According to an embodiment, an electronic device used to be coupled toan SD memory card device and capable of controlling a data transmissionmode of the SD memory card device is disclosed. The electronic device isat a host and has a first external signal port. The SD memory carddevice at least operates under an SD mode and has a second externalsignal port. The electronic device comprises the first external signalport, a driving circuit, and a processor. The first external signal porthas multiple pins and is coupled to multiple pins of the second externalsignal port of the SD memory card device. The driving circuit is coupledto the first external signal port. The processor is coupled to thedriving circuit and used for: controlling the driving circuit to send afirst power signal corresponding to the SD mode from the electronicdevice to the SD memory card device via the first external signal portand a pin VDD1 Of the second external signal port, to control and makethe SD memory card device enter an initial state; and sending a secondpower signal from the electronic device to the SD memory card device viaone of a pin VDD2 and a pin VDD3 of the second external signal port, tocontrol and make the SD memory card device enter a Linkup state of aPCIe mode, a voltage level of the second power signal being lower than avoltage level of the first power signal. A plurality of pins, used for adata line, of an UHS-I input/output communication interface standardemployed by the SD mode of the SD memory card device are shared byanother input/output communication interface standard of a PCIe channelwith an NVMe protocol employed by the PCIe mode, and the plurality ofpins of the UHS-I input/output communication interface standard employedby the SD mode comprise pins of pin numbers 1, 7, 8, and 9.

According to an embodiment, a method for controlling a data transmissionmode of an SD memory card device is disclosed. The electronic is used asa host and has a first external signal port. The SD memory card deviceat least one operates an SD mode and has a second external signal port,and the SD memory card device is coupled to the electronic device viathe first external signal port and the second external signal port. Themethod comprises: sending a first power signal corresponding to the SDmode from the electronic device used as the host to the SD memory carddevice via the first external signal port and a pin VDD1 of the secondexternal signal port, to control and make the SD memory card deviceenter an initial state; sending a command CMD0 corresponding to the SDmode from the electronic device to the SD memory card device via pin CMDemployed by the SD mode or sending a specific clock SDCLK correspondingto the SD mode from the electronic device to the SD memory card devicevia pin CLK employed by the SD mode, to control and make the SD memorycard device enter the SD mode from the initial state and operate underthe SD mode; sending a command CMD8 from the electronic device to the SDmemory card device via the pin CMD to query whether the SD memory carddevice supports a PCIe mode; controlling the SD memory card device tooperate under the SD mode if the SD memory card device responses thatthe PCIe mode is not supported; and sending a second power signal fromthe electronic device to the SD memory card device via one of a pin VDD2and a pin VDD3 of the second external signal port if the SD memory carddevice responses that the PCIe mode is supported, to control and makethe SD memory card device enter a Linkup state of the PCIe mode, avoltage level of the second power signal being lower than a voltagelevel of the first power signal. A plurality of pins of an UHS-Iinput/output communication interface standard employed by the SD mode ofthe SD memory card device, used for a data line, are shared to be usedby another input/output communication interface standard of PCIe channelwith NVMe protocol employed by the PCIe mode; the plurality of pins usedas the data line in the SD mode comprise pins of pin numbers 1, 7, 8,and 9.

According to an embodiment, an electronic device to be coupled to an SDmemory card device and capable of controlling a data transmission modeof the SD memory card device is disclosed. The electronic device is at ahost and has a first external signal port. The SD memory card device atleast can operate under an SD mode and have a second external signalport. The electronic device comprises the first external signal port, adriving circuit, and a processor. The first external signal port has aplurality of pins to be coupled to multiple pins of the second externalsignal port of the SD memory card device. The driving circuit is coupledto the first external signal port. The processor is coupled to thedriving circuit and configured for: controlling the driving circuit tosend a first power signal corresponding to the SD mode from theelectronic device to the SD memory card device through the firstexternal signal port and a pin VDD1 of the second external signal port,to control and make the SD memory card device enter an initial state;controlling the driving circuit to send a command CMD0 corresponding tothe SD mode from the electronic device to the SD memory card devicethrough the pin CMD employed by the SD mode or to send a specific clockSDCLK corresponding to the SD mode from the electronic device to the SDmemory card device through a pin CLK employed by the SD mode, to controland make the SD memory card device enter the SD mode from the initialstate and operate under the SD mode; controlling the driving circuit tosend a command CMD8 from the electronic device to the SD memory carddevice through the pin CMD to query whether the SD memory card devicesupports a PCIe mode; controlling the SD memory card device to operateunder the SD mode if the SD memory card device responses that the PCIemode is not supported; and sending a second power signal from theelectronic device to the SD memory card device via one of a pin VDD2 anda pin VDD3 of the second external signal port if the SD memory carddevice responses that the PCIe mode is supported, to control and makethe SD memory card device enter a Linkup state of the PCIe mode, avoltage level of the second power signal being lower than a voltagelevel of the first power signal. A plurality of pins of an UHS-Iinput/output communication interface standard employed by the SD mode ofthe SD memory card device, used for a data line, are shared to be usedby another input/output communication interface standard of PCIe channelwith NVMe protocol employed by the PCIe mode; the plurality of pins usedas the data line in the SD mode comprise pins of pin numbers 1, 7, 8,and 9.

According to an embodiment, a method used in an SD memory card device isdisclosed. An electronic device used as a host has a first externalsignal port. The SD memory card device can at least operate under an SDmode and have a second external signal port, and the SD memory carddevice is coupled to the electronic device through the first externalsignal port and the second external signal port. The method comprises:receiving a first power signal corresponding to the SD mode from theelectronic device through the first external signal port and a pin VDD1of the second external signal port, to control and make the SD memorycard device enter an initial state; and receiving a second power signalfrom the electronic device through one among a pin VDD2 and a pin VDD3of the second external signal port, a voltage level of the second powersignal being lower than a voltage level of the first power signal. Aplurality of pins of an UHS-I input/output communication interfacestandard employed by the SD mode of the SD memory card device, used fora data line, are shared to be used by another input/output communicationinterface standard of PCIe channel with NVMe protocol employed by thePCIe mode; the plurality of pins used as the data line in the SD modecomprise pins of pin numbers 1, 7, 8, and 9.

According to an embodiment, a flash memory controller of an SD memorycard device is disclosed. The SD memory card device is coupled to anelectronic device, and the electronic device is at a host and has afirst external signal port. The SD memory card device at least canoperate under an SD mode and have a second external signal port. Thesecond external signal port has multiple pins to be coupled multiplepins of the first external signal port of the electronic device. The SDmemory card device further comprises a flash memory, and the flashmemory controller is coupled between the flash memory and the secondexternal signal port. The flash memory controller comprises a registerand a processing circuit. The register is configured for temporarilystoring information of the flash memory. The processing circuit iscoupled to the register and configured for: receiving a first powersignal, corresponding to the SD mode, sent from the electronic devicethrough the first external signal port and a pin VDD1 of the secondexternal signal port, to control and make the SD memory card deviceenter an initial state; and receiving a second power signal sent fromthe electronic device through one among a pin VDD2 and a pin VDD3 of thesecond external signal port, to control and make the SD memory carddevice enter a Linkup state of a PCIe mode, a voltage level of thesecond power signal being lower than a voltage level of the first powersignal. A plurality of pins, used for a data line, of an UHS-Iinput/output communication interface standard employed by the SD mode ofthe SD memory card device are shared to be used by another input/outputcommunication interface standard of a PCIe channel with an NVMe protocolemployed by the PCIe mode; the plurality of pins used as the data linein the SD mode comprise pins of pin numbers 1, 7, 8, and 9.

According to an embodiment, a method used in an SD memory card device isdisclosed. An electronic device used as a host has a first externalsignal port. The SD memory card device at least can operate under an SDmode and have a second external signal port, and the SD memory carddevice is coupled to the electronic device through the first externalsignal port and the second external signal port. The method comprises:receiving a first power signal, corresponding to the SD mode, sent fromthe electronic device through the first external signal port and a pinVDD1 of the second external signal port, to make the SD memory carddevice enter an initial state; receiving a command CMD0, correspondingto the SD mode, sent from a pin CMD employed by the SD mode from theelectronic device or a specific clock SDCLK, corresponding to the SDmode, sent from a pin CLK employed by the SD mode from the electronicdevice, to make the SD memory card device enter the SD mode from theinitial state and operate under the SD mode; receiving a command CMD8sent from the electronic device through the pin CMD wherein the commandCMD8 is used to query whether the SD memory card device supports a PCIemode; responding the electronic device that the SD memory card devicedoes not support the PCIe mode and maintain at the SD mode if the PCIemode is not supported; and responding the electronic device that the SDmemory card device supports the PCIe mode if the PCIe mode is supported,and then receiving a second power signal sent from the electronic devicethrough one among a pin VDD2 and a pin VDD3 of the second externalsignal port, to make the SD memory card device enter a Linkup state ofthe PCIe mode, a voltage level of the second power signal being lowerthan a voltage level of the first power signal. A plurality of pins,used for a data line, of an UHS-I input/output communication interfacestandard employed by the SD mode of the SD memory card device are sharedto be used by another input/output communication interface standard of aPCIe channel with an NVMe protocol employed by the PCIe mode; theplurality of pins used as the data line in the SD mode comprise pins ofpin numbers 1, 7, 8, and 9.

According to an embodiment, a flash memory controller of an SD memorycard device is disclosed. The SD memory card device is coupled to anelectronic device. The electronic device is at a host and has a firstexternal signal port. The SD memory card device at least can operateunder an SD mode and have a second external signal port, and the secondexternal signal port has multiple pins to be coupled to multiple pins ofthe first external signal port of the electronic device. The SD memorycard device further has a flash memory, and the flash memory controlleris coupled between the flash memory and the second external signal port.The flash memory controller comprises a register and a processingcircuit. The register is used for temporarily storing information of theflash memory. The processing circuit is coupled to the register and usedfor: receiving a first power signal, corresponding to the SD mode, sentfrom the first external signal port and a pin VDD1 of the secondexternal signal port from the electronic device, to control and make theSD memory card device enter an initial state; receiving a command CMD0,corresponding to the SD mode, through the pin CMD employed by the SDmode sent from the electronic device or a specific clock SDCLK,corresponding to the SD mode, through a pin CLK employed by the SD modesent from the electronic device, to control and make the SD memory carddevice enter the SD mode from the initial state and operated under theSD mode; receiving a command CMD8 through the pin CMD sent from theelectronic device, the command CMD8 being used for querying whether theSD memory card device supports a PCIe mode; using the processing circuitto respond the electronic device that the secure digital memory carddevice does not support the PCIe mode and maintaining the SD memory carddevice at the SD mode if the SD memory card device does not support thePCIe mode; and using the processing circuit to respond the electronicdevice that the SD memory card device supports the PCIe mode and thenreceiving a second power signal through one among a pin VDD2 and a pinVDD3 of the second external signal port sent from the electronic deviceif the SD memory card device supports the PCIe mode, to control and makethe SD memory card device enter a Linkup state of the PCIe mode, avoltage level of the second power signal being lower than a voltagelevel of the first power signal. A plurality of pins, used for a dataline, of an UHS-I input/output communication interface standard employedby the SD mode of the SD memory card device are shared to be used byanother input/output communication interface standard of a PCIe channelwith an NVMe protocol employed by the PCIe mode, and the plurality ofpins of the UHS-I input/output communication interface standard employedby the SD mode comprise pins of pin numbers 1, 7, 8, and 9.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart diagram of a method for controlling the datatransmission mode of a memory card device according to a firstembodiment of the invention.

FIG. 2 is a flowchart diagram of a method for controlling a datatransmission mode of a memory card device according to a secondembodiment of the invention.

FIG. 3 is a diagram showing two memory card devices respectively havingdifferent numbers of pins.

FIG. 4 is state switching diagram of the data transmission mode of amemory card device according to an embodiment of the invention.

FIG. 5 is a block diagram of implementations of the memory card device(e.g. an SD memory card device) and the electronic device as the hostaccording to the method disclosed in the embodiments of the invention.

FIG. 6 is a diagram of examples of signals at a portion of pins when theelectronic device as a host and shown on FIG. 5 directly controls thememory card device entering the PCIe mode from the initial state.

DETAILED DESCRIPTION

The invention aims at providing a mechanism of a memory card devicehaving different data transmission modes. The different datatransmission modes for example can be a secure digital (SD) modesupporting the data transmission of an SD memory card and a PCIe(Peripheral Component Interconnect Express) mode supporting the datatransmission of a PCIe channel with a NVMe protocol (NVM Expressprotocol), i.e. the PCIe mode is implemented by employing the physicallayer of PCIe channel interface on which the NVMe protocol runs and thuscan also be called the PCIe/NVMe mode. The different data transmissionmodes share and use at least one signal pin of an external communicationsignal port of the memory card device. In addition, the providedmechanism of the invention can protect and prevent the memory carddevice from circuit damage caused due to that actual voltage of thesignal level becomes different when the memory card device switchesbetween the different data transmission modes, and/or to make the datatransmission between the memory card device and an electronic devicewhich is used as a host adopt a data transmission mode with a fasterdata rate so as to improve the transmission rate.

Conventional SD memory card devices produced by a manufacturer and soldon the market generally have a fewer pins. For example, a conventionalSD memory card device may have signal pins of only one row and supportone data transmission mode such as SD mode; the conventional SD memorycard device perform data communication with an electronic device as ahost through an UHS-I input/output communication interface standardspecified by the SD mode.

The invention provides a novel memory card device having different datatransmission modes and having more pins. For example, the novel memorycard device may have signal pins of a first row and signal pins of asecond row, and supports different data transmission interfaces such asthe UHS-I input/output communication interface standard specified by theSD mode and the PCIe mode supporting the PCIe channel interface with theNVMe protocol. The provided memory card device can perform datacommunication with the electronic device as the host through thespecified different communication standards. In addition, for theelectronic device used as the host, its driving circuits and/or versioninformation of driver programs may be classified into the drivingcircuit and/or driver programs which can support a fewer signal pins andonly SD mode and the driving circuit and/or driver programs which cansupport the more signal pins and additional PCIe mode.

It should be noted that the values of actually specified voltage levelsof the signal logic levels of input/output communication interfacestandards respectively employed by the SD mode and PCIe mode forperforming data transmission are different. In some situations, thecircuits of the memory card device may be damaged due to the differentspecified voltage levels of the signal logic levels of input/outputcommunication interface standards.

Thus, in order to avoid the circuit damage as well as to more rapidlycontrol the memory card device entering a data transmission mode capableof supporting a higher data transmission speed, a novel method forcontrolling a memory card device to switch between SD mode and PCIe modeis provided in the embodiments of the invention.

In the embodiments of the invention, the memory card device for exampleis an SD memory card device (but not limited). The memory card disclosedin the invention has more pins which are arranged in two rows and cansupport both SD mode and PCIe mode. The memory card device can operateunder either SD mode or PCIe mode. The memory card device respectivelyoperating under the SD mode and PCIe mode shares and uses at least onepin of an external communication port of the memory card device toperform communication with an electronic device used as a host. Thefirst table in the following lists the pin numbers, names, types,descriptions of the pins employed by the SD mode, and the second tablelists the pin numbers, names, types, descriptions of the pins employedby the PCIe mode:

Pin SD mode Number Name Type Description 1 CD/DAT3 I/O/PP Carddetect/Data line 3 [bit 3] 2 CMD I/O/PP Command/Response 3 VSS1 S Ground4 VDD S Supply voltage 5 CLK I Clock 6 VSS2 S Ground 7 DAT0 I/O/PP Dataline 0 [bit 0] 8 DAT1 I/O/PP Data line 1 [bit 1] 9 DAT2 I/O/PP Data line2 [bit 2]

wherein S means the supply voltage, I means the input, O means theoutput of push-pull driving, and PP means input/output of push-pulldriving. The above-mentioned commands are transmitted through the pinCMD, and data to be transmitted is sent via the pins DAT0, DAT1, DAT2,and CD/DAT3.

PCIe mode Pin Number Name Type Description  1 PERST# Input signalPE-Reset is a function (active low) reset to the card as defined by thePCIe Mini CEM specification  4 VDD1 Supply 2.7 V to 3.6 V voltage  7REFCLK+ Differential Clock Input Signaling: Input  8 REFCLK−Differential Clock Input Signaling: Input  9 CLKREQ# I/O (activeReference clock low, open request signal. Also drain) used by L1 PMsubstates 10 VSS3 Ground 11 PCIe TX+ Differential Card Input Signaling12 PCIe TX− Differential Card Input Signaling 13 VSS4 Ground 14 VDD2Supply 1.70 V to 1.95 V Voltage 2 15 PCIe RX− Differential Card OutputSignaling 16 PCIe RX+ Differential Card Output Signaling 17 VSS5 Ground 18* VDD3 Supply 1.14 V to 1.30 V Voltage 3

wherein the symbol ‘*’ means that the pin is reserved for the supplyvoltage 3. The pins having pin numbers 1, 7, 8, and 9 (but not limited)are shared and respectively used by the operations of the SD mode andPCIe mode for the memory card device. It should be noted that theabove-mentioned examples are not meant to be a limitation of theinvention. The method and flowchart provided in one embodiment of theinvention is for example applied into a driving circuit of an electronicdevice used as a host wherein such driving circuit is used forcontrolling a memory card device entering to operate under the SD modeor PCIe mode so as to avoid circuit damage as well as improve datatransmission efficiency.

Please refer to FIG. 1. FIG. 1 is a flowchart diagram of a method forcontrolling the data transmission mode of a memory card device accordingto a first embodiment of the invention. Provided that substantially thesame result is achieved, the steps of the flowchart shown in FIG. 1 neednot be in the exact order shown and need not be contiguous, that is,other steps can be intermediate. Steps are detailed in the following:

Step 105: Start;

Step 110: An electronic device as a host sends a first power signal froma driving circuit of the electronic device to the memory card devicethrough a pin VDD1, to control and make the memory card device enter aninitial state which is a pseudo initial state;

Step 115: Send a specific command such as command CMD0, corresponding tothe SD mode, from the driving circuit of the electronic device to thememory card device through a pin CMD and/or send a specific clock SDCLK,corresponding to the SD mode, from the driving circuit of the electronicdevice to the memory card device through a pin CLK, to control and makethe memory card device enter the SD mode from the initial state andoperate under the SD mode;

Step 120: Send a command CMD8 from the driving circuit of the electronicdevice to the memory card device through the pin CMD to query whetherthe memory card device supports the PCIe mode and to wait for aresponse/reply of the memory card device; if the memory card devicereplies that it supports the PCIe mode, then the flow proceeds to Step125; otherwise, if the memory card device replies that it does notsupport the PCIe mode, then the flow proceeds to Step 150;

Step 125: Send or enable a second power signal, corresponding to thePCIe mode, from the driving circuit of the electronic device as the hostto the memory card device through the pin VDD2 or pin VDD3, to controland make the memory card device enter a Linkup state of the PCIe modefrom the SD mode;

Step 130: The memory card device in the Linkup state of the PCIe modecommunicates with the electronic device as the host based on acommunication connection protocol and the electronic device determineswhether the communication connection protocol succeeds; if thecommunication connection protocol succeeds, then the flow proceeds toStep 135; otherwise, if the communication connection protocol fails,then the flow proceeds to Step 140;

Step 135: The electronic device controls the memory card device operateunder the PCIe mode;

Step 140: The electronic device determines whether to retry aconnection; if determining to retry a connection, then the flow proceedsto Step 130; otherwise, if determining not to retry a connection, thenthe flow proceeds to Step 145;

Step 145: Send the command CMD0, corresponding to the SD mode, from thedriving circuit of the electronic device to the memory card devicethrough the pin CMD and/or send the specific clock SDCLK, correspondingto the SD mode, from the driving circuit of the electronic device to thememory card device through the pin CLK, to control and make the memorycard device enter the SD mode from the Linkup state of the PCIe mode andoperate under the SD mode;

Step 150: Maintain at the SD mode; and

Step 155: End.

Further, in one embodiment, the electronic device as the host candetermine not to control the memory card device entering the SD mode andinstead determine to send the second power signal to the memory carddevice through the pin VDD2 or pin VDD3 to try to control the memorycard device entering the PCIe mode at first. Please refer to FIG. 2.FIG. 2 is a flowchart diagram of a method for controlling a datatransmission mode of a memory card device according to a secondembodiment of the invention. Provided that substantially the same resultis achieved, the steps of the flowchart shown in FIG. 2 need not be inthe exact order shown and need not be contiguous, that is, other stepscan be intermediate. Steps are detailed in the following:

Step 205: Start;

Step 210: The electronic device as the host sends the first power signalfrom the driving circuit of the electronic device to the memory carddevice through the pin VDD1, to control and make the memory card deviceenter the pseudo initial state;

Step 215: Send or enable the second power signal, corresponding to thePCIe mode, from the driving circuit of the electronic device as the hostto the memory card device through the pin VDD2 or pin VDD3, to controland make the memory card device enter the Linkup state of the PCIe modeform the SD mode;

Step 220: In the Linkup state of the PCIe mode the memory card devicecommunicates with the electronic device at the host based on thecommunication connection protocol and the electronic device determineswhether the communication connection protocol succeeds; if thecommunication connection protocol succeeds, then the flow proceeds toStep 225; otherwise, if the communication connection protocol fails,then the flow proceeds to Step 230;

Step 225: The electronic device controls the memory card device operateunder the PCIe mode;

Step 230: The electronic device determines whether to retry aconnection; if determining to retry a connection, then the flow proceedsto Step 220; otherwise, if determining not to retry a connection, thenthe flow proceeds to Step 235;

Step 235: Send the command CMD0, corresponding to the SD mode, from thedriving circuit of the electronic device to the memory card devicethrough the pin CMD and/or send the specific clock SDCLK, correspondingto the SD mode, from the driving circuit of the electronic device to thememory card device through the pin CLK, to control and make the memorycard device enter the SD mode from the Linkup state of the PCIe mode andoperate under the SD mode; and

Step 240: End.

FIG. 3 is a diagram showing two memory card devices respectively havingdifferent numbers of pins. For example, the memory card device shown onthe left side of FIG. 3 has nine pins of only a single row and forexample is an SD memory card supporting the first generation UHS (UHS-I)data transmission interface. The memory card device disclosed by theembodiments is the memory card device shown on the right side of FIG. 3having eighteen pins totally arranged in two rows, and it for example isan SD memory card supporting the UHS-I input/output communicationinterface standard specified in the SD mode as well as supporting thePCIe channel interface with NVMe protocol specified in the PCIe mode.

Please refer to FIG. 4. FIG. 4 is state switching diagram of the datatransmission mode of a memory card device according to an embodiment ofthe invention. In this embodiment, the memory card device is a memorycard device supporting both the SD mode and PCIe mode. That is, the SDmode means a first mode having a data transmission rate lower than amaximum data transmission rate of a second mode such as PCIe mode. Thefirst power signal at the pin VDD1 is for example equal to 3.3 Voltsdifferent from the second power signal, e.g. 1.2 volts at pin VDD3 or1.8 Volts at pin VDD2. However, this is not meant to be a limitation.For the SD memory card device supporting both the SD mode and PCIe mode,as shown in the flowcharts of FIG. 1 and FIG. 2, the electronic deviceas the host can control the SD memory card device operate under the SDmode at first and then try to control and make it enter the PCIe mode.Alternatively, the electronic device as the host can directly controlthe SD memory card device trying to enter the PCIe mode, and control theSD memory card device entering the SD mode if the SD memory card devicecannot enter the PCIe mode.

For the initialization of the SD memory card device, the electronicdevice as the host is used to send the first power signal such as 3.3Volts to the SD memory card device through the pin VDD1 of the externalsignal port, and thus the SD memory card device then enters the pseudoinitial state.

In the pseudo initial state, as indicated by the flowchart of FIG. 1,the electronic device can send the specific command CMD0 correspondingto the SD mode or the specific clock SDCLK corresponding to the SD modeto the SD memory card device, to control the SD memory card deviceentering the SD mode from the initial state. Alternatively, as shown bythe flowchart of FIG. 2, the electronic device can send or enable thesecond power signal such as 1.8 Volts or 1.2 Volts corresponding to thePCIe mode from the electronic device to the SD memory card devicethrough the pin VDD2 or pin VDD3, to control the SD memory card devicedirectly entering the Linkup state of the PCIe mode from the initialstate.

When the SD memory card device operates under the SD mode, theelectronic device can control the SD memory card device trying to enterthe PCIe mode by sending or enabling the second power signalcorresponding to the PCIe mode from the electronic device to the SDmemory card device through the pin VDD2 or pin VDD3, to control and makethe SD memory card device enter the Linkup state of the PCIe mode fromthe SD mode.

When the SD memory card device is in the Linkup state of the PCIe mode,the electronic device can control the SD memory card device entering theSD mode by sending the specific command CMD0 corresponding to the SDmode or the specific clock SDCLK corresponding to the SD mode to the SDmemory card device, to control and make the SD memory card device enterthe SD mode from the Linkup state of the PCIe mode. The Linkup state ofthe PCIe mode means a state of waiting for a connection result of thecommunication connection protocol before the SD memory card deviceenters the PCIe mode. Thus, even though an SD memory card device doesnot support the PCIe mode, it is possible that the SD memory card devicemay enter the state of waiting for the connection result. Accordingly,if the connection result is fail (i.e. the communication connectionprotocol fails), then the electronic device sends the specific commandCMD0 corresponding to the SD mode or the specific clock SDCLKcorresponding to the SD mode to the SD memory card device to control theSD memory card device entering the SD mode from the state of waiting forthe connection result. When the connection result is pass (i.e. thecommunication connection protocol succeeds), then the electronic devicecontrols the SD memory card device entering the PCIe mode from theLinkup state of PCIe mode.

When operating under the PCIe mode, the SD memory card device can exitthe PCIe mode and go back to the Linkup state of PCIe mode.Alternatively, the electronic device can control and make the SD memorycard device go back to the pseudo initial state from the PCIe mode bydisabling the second power signal, corresponding to the PCIe mode, atthe pin VDD2 or pin VDD3.

For example, when the SD memory card device operates under the PCIemode, a communication bottom layer between the SD memory card device andthe electronic device as the host is arranged to record a registerLinkup parameter which can be temporarily stored within the electronicdevice. For example, the register Linkup parameter stored in acorresponding driving circuit of the electronic device (but notlimited). When the connection result of the SD memory card deviceoperating under the PCIe mode becomes fail, the register Linkupparameter becomes zero, and the SD memory card device exits the PCIemode and goes back to the Linkup state of the PCIe mode. In thissituation, the electronic device controls the SD memory card deviceretry the connection again. The times of trying re-connection depends onthe design of the electronic device; this is not meant to be alimitation. To perform the above mentioned operations, the electronicdevice can dynamically control the SD memory card device to switchbetween different modes in response to different requirements of systemperformances. It is not necessary for the SD memory card device to haveto operate under the mode having a faster data transmission rate.

When the SD memory card device is at the Linkup state of PCIe mode, theelectronic device can control the SD memory card device entering thepseudo initial state by disabling the second power signal at the pinVDD2 or pin VDD3.

Please refer to FIG. 5. FIG. 5 is a block diagram of implementations ofthe memory card device 400 (e.g. an SD memory card device) and theelectronic device 405 as the host according to the method disclosed inthe embodiments of the invention. The memory card device 400 comprisesan external signal port 4001, the flash memory 410, and the flash memorycontroller 420. The controller 420 is coupled between the externalsignal port 4001 and flash memory 410, and is connected to the flashmemory 410 through an internal bus. The flash memory controller 420comprises a register 415 and a processing circuit 416. The register 415can be used to temporarily store basic data of the flash memory 410. Theprocessing circuit 416 is used to execute corresponding operations ofthe flash memory controller 420, e.g. data/signal reception andtransmission of above-mentioned input/output interface, access,computation, and so on. The flash memory 410 comprises one or more flashmemory chips. The electronic device 405 comprises the external signalport 4055, memory card driving circuit 4051, and processor 4053. Theelectronic device 405 is coupled to the memory card device 400 throughthe signal ports 4055 and 4001 which respectively comprise multiplecorresponding pins. The memory card device 400 at least can operateunder the SD mode. The processor 4053 is used for controlling thedriving circuit 4051 to send the first power signal, corresponding tothe SD mode, to the memory card device 400 through the external signalport 4055 and the pin VDD1 of external signal port 4001. When thecontroller 420 detects the first power signal at the pin VDD1, thecontroller 420 accordingly controls the memory card device 400 enteringthe initial state. In addition, the memory card device 400 can furtheroperate under the PCIe mode. A portion of pins of the external signalport 4001, e.g. the pins having pin numbers 1, 7, 8, and 9, are sharedand used by the operations of memory card device 400 respectivelyoperating under the both SD mode and PCIe mode.

In addition, the processor 4053 controls the driving circuit 4051 tosend the second power signal, corresponding to the PCIe mode, from theelectronic device 405 to the memory card device 400 through the pin VDD2or to send the second power signal, corresponding to the PCIe mode, fromthe electronic device 405 to the memory card device 400 through the pinVDD3. The controller 420 is arranged to detect the second power signalat the pin VDD2 or pin VDD3. For example, when detecting that the secondpower signal is at the pin VDD3, the controller 420 can accordinglycontrol and make the memory card device 400 enter the Linkup state ofPCIe mode from the initial state. In the Linkup state of PCIe mode, theprocessor 4053 communicates with the controller 420 of memory carddevice 400 based on a communication connection protocol through thedriving circuit 4051, the external signal port 4055, and the externalsignal port 4001. If the communication connection protocol succeeds,then the memory card device 400 operates under the PCIe mode. If thecommunication connection protocol fails, then the driving circuit 4051can determine whether to retry a connection. If determining not to retrya connection, then the memory card device 400 is controlled to enter theSD mode from the Linkup state.

In addition, in the Linkup state of PCIe mode, the processor 4053 canalso control the driving circuit 4051 to disable the second power signalof PCIe mode sent at the pin VDD2 or pin VDD3 through the drivingcircuit 4051, external signal port 4055, and external signal port 4001,to accordingly control and make the memory card device 400 go back tothe initial state from the Linkup state of PCIe mode.

In addition, the processor 4053 can control the driving circuit 4051 tosend at least one of the specific command such as CMD0 corresponding tothe SD mode and the specific clock SDCLK corresponding the SD mode fromthe electronic device 405 to the control 420 of the memory card device400 through the driving circuit 4051, external signal port 4055, andexternal signal port 4001, to accordingly control and make the memorycard device 400 enter the SD mode from the initial state.

FIG. 6 is a diagram of examples of signals at a portion of pins when theelectronic device 405 as a host and shown on FIG. 5 directly controlsthe memory card device 400 entering the PCIe mode from the initialstate. As shown in FIG. 6, the electronic device 405 as the host atfirst is arranged to raise a low voltage level at the pin CMD, e.g. 0Volts, to a high voltage level such as 3.3 Volts or 1.8 Volts, and alsoto raise the level at the pin CLKREQ #from 0 Volts to 3.3 Volts or 1.8Volts and raise the level at the pin VDD1 from a low voltage level suchas 0 Volts to a high voltage level such as 3.3 Volts to provide thefirst power signal to the memory card device 400 to control the memorycard device 400 entering the initial state.

In this embodiment, the electronic device 405 determines to directlycontrol the memory card device 400 trying to enter the PCIe mode, andthus in the initial state is arranged to directly provide the secondpower signal to raise the level at the pin VDD3 from a low voltagelevel, e.g. 0 Volts, to a high voltage level such as 1.2 Volts. Itshould be noted that the electronic device 405 can raise the level atthe pin VDD2 from the low voltage level, e.g. 0 Volts, to the highvoltage level such as 1.8 Volts so as to provide the second powersignal. This depends on the design of the electronic device 405 andwhether the memory card device 400 supports the pin VDD3. If the memorycard device 400 does not support the pin VDD3, then the electronicdevice 405 can try to raise the level at the pin VDD2 from the lowvoltage level, e.g. 0 Volts, to the high voltage level such as 1.8 Voltsor try to directly control the memory card device 400 entering the SDmode.

Accordingly, in the embodiment of FIG. 6, when the memory card device400 detects that the level at the pin VDD3 is raised from 0 Volts to 1.2Volts, the memory card device 400 can enter the Linkup state of PCIemode. In the Linkup state of PCIe mode, the memory card device 400reduces the level at the pin CLKREQ #from 3.3 Volts or 1.8 Volts to 0Volts, to notify the electronic device 405 of that the memory carddevice 400 has received a connection request of PCIe mode and has beenready to receive the clock input signal provided by the electronicdevice 405. The electronic device 405 as the host is arranged to waitfor at most 1 ms to detect whether the level at the pin CLKREQ #isreduced from the high voltage level to the low voltage level. If thelevel is reduced to the low voltage level, then the electronic device405 starts to transmit differential clock input signals, e.g. thewaveforms having levels in the range from 0.8 Volts to 1.2 Volts,through the pins REFCLK− and REFCLK+ to the memory card device 400 andto determine whether it is able to stably provide the differential clockinput signals for example at least 100 microseconds. If it is able tostably provide the differential clock input signals, then the electronicdevice 405 raises the level at the pin PERST #from the low voltage levelsuch as 0 Volts to the high voltage level such as 3.3 Volts or 1.8 Voltsand then starts link training of PCIe mode. After the link training hasbeen completed, the memory card device 400 can operate under the PCIemode and perform the initialization of PCIe mode.

If the operation in the Linkup state of PCIe mode is fail, then thememory card device 400 enters the SD mode and the electronic device 405is arranged to access the memory card device 4090 through the UHS-I datatransmission interface under the SD mode. The operation which is failmay be generated due to that the level at pin CLKREQ #is always at thehigh voltage level and is not reduced by the memory card device 400 orthe link training of PCIe mode has been failing; however, this is notintended to be a limitation.

Further, it should be noted that in the embodiment of FIG. 6, since noclock signal SDCLK corresponding to the SD mode is received, e.g. thelevel of signal SDCLK is keep at the low voltage level 0 Volts, thememory card device 400 does not enter the SD mode from the initialstate.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

What is claimed is:
 1. A method for controlling a data transmission modeof a secure digital (SD) memory card device, an electronic device to beused as a host and having a first external signal port, the SD memorycard device to be capable of operating an SD mode at least and having asecond external signal port, the SD memory card device to be coupled tothe electronic device via the first external signal port and the secondexternal signal port, and the method comprises: sending a first powersignal corresponding to the SD mode from the electronic device to the SDmemory card device via the first external signal port and a pin VDD1 ofthe second external signal port, to control and make the SD memory carddevice enter an initial state; sending a second power signal from theelectronic device to the SD memory card device via one of a pin VDD2 anda pin VDD3 of the second external signal port, to control and make theSD memory card device enter a Linkup state of a peripheral componentinterconnect express WOO mode, a voltage level of the second powersignal being lower than a voltage level of the first power signal; usingthe electronic device in the Linkup state of the PCIe mode tocommunicate with the SD memory card device based on a communicationconnection protocol; operating the SD memory card device under the PCIemode if the communication connection protocol succeeds; and sending acommand CMD0 corresponding to the SD mode at a pin CMD employed by theSD mode or sending a specific clock SDCLK corresponding to the SD modeat a pin CLK employed by the SD mode from the electronic device to theSD memory card device via the first external signal port and the secondexternal signal port, to control and make the SD memory card deviceenter the SD mode from the Linkup state if the communication connectionprotocol fails; wherein a plurality of pins, used for a data line, of afirst generation Ultra High Speed (UHS-I) input/output communicationinterface standard employed by the SD mode of the SD memory card deviceare shared by another input/output communication interface standard of aPCIe channel with an non-volatile memory express (NVMe) protocolemployed by the PCIe mode, and the plurality of pins of the UHS-Iinput/output communication interface standard employed by the SD modecomprise pins of pin numbers 1, 7, 8, and
 9. 2. The method of claim 1,further comprising: in the Linkup state of the PCIe mode, disabling thesecond power signal of the PCIe mode from the electronic device via thefirst external signal port and the second external signal port, tocontrol the SD memory card device to go back to the initial state fromthe Linkup state.
 3. An electronic device used to be coupled to an SDmemory card device and capable of controlling a data transmission modeof the SD memory card device, the electronic device to be at a host andhaving a first external signal port, the SD memory card device at leastoperating under an SD mode and having a second external signal port, andthe electronic device comprises: the first external signal port havingmultiple pins and to be coupled to multiple pins of the second externalsignal port of the SD memory card device; a driving circuit, coupled tothe first external signal port; and a processor, coupled to the drivingcircuit, and used for: controlling the driving circuit to send a firstpower signal corresponding to the SD mode from the electronic device tothe SD memory card device via the first external signal port and a pinVDD1 of the second external signal port, to control and make the SDmemory card device enter an initial state; sending a second power signalfrom the electronic device to the SD memory card device via one of a pinVDD2 and a pin VDD3 of the second external signal port, to control andmake the SD memory card device enter a Linkup state of a PCIe mode, avoltage level of the second power signal being lower than a voltagelevel of the first power signal; communicating with the SD memory carddevice based on a communication connection protocol in the Linkup stateof the PCIe mode; operating the SD memory card device under the PCIemode if the communication connection protocol succeeds; and sending acommand CMD0 corresponding to the SD mode at a pin CMD employed by theSD mode or sending a specific clock SDCLK corresponding to the SD modeat a pin CLK employed by the SD mode from the electronic device to theSD memory card device via the first external signal port and the secondexternal signal port, to control and make the SD memory card device toenter the SD mode from the Linkup state if the communication connectionprotocol fails; wherein a plurality of pins, used for a data line, of anUHS-I input/output communication interface standard employed by the SDmode of the SD memory card device are shared by another input/outputcommunication interface standard of a PCIe channel with an NVMe protocolemployed by the PCIe mode, and the plurality of pins of the UHS-Iinput/output communication interface standard employed by the SD modecomprise pins of pin numbers 1, 7, 8, and
 9. 4. The electronic device ofclaim 3, wherein when the SD memory card device in the Linkup state ofthe PCIe mode, the processor is used for controlling the driving circuitto disable the second power signal of the PCIe mode via the firstexternal signal port and the second external signal port, to control theSD memory card device to go back to the initial state from the Linkupstate.
 5. A method for controlling a data transmission mode of an SDmemory card device, an electronic to be used as a host and having afirst external signal port, the SD memory card device at least operatesan SD mode and has a second external signal port, the SD memory carddevice to be coupled to the electronic device via the first externalsignal port and the second external signal port, and the methodcomprises: sending a first power signal corresponding to the SD modefrom the electronic device used as the host to the SD memory card devicevia the first external signal port and a pin VDD1 of the second externalsignal port, to control and make the SD memory card device enter aninitial state; sending a command CMD0 corresponding to the SD mode fromthe electronic device to the SD memory card device via pin CMD employedby the SD mode or sending a specific clock SDCLK corresponding to the SDmode from the electronic device to the SD memory card device via pin CLKemployed by the SD mode, to control and make the SD memory card deviceenter the SD mode from the initial state and operate under the SD mode;sending a command CMD8 from the electronic device to the SD memory carddevice via the pin CMD to query whether the SD memory card devicesupports a PCIe mode; controlling the SD memory card device to operateunder the SD mode if the SD memory card device responses that the PCIemode is not supported; and sending a second power signal from theelectronic device to the SD memory card device via one of a pin VDD2 anda pin VDD3 of the second external signal port if the SD memory carddevice responses that the PCIe mode is supported, to control and makethe SD memory card device enter a Linkup state of the PCIe mode, avoltage level of the second power signal being lower than a voltagelevel of the first power signal; wherein a plurality of pins of an UHS-Iinput/output communication interface standard employed by the SD mode ofthe SD memory card device, used for a data line, are shared to be usedby another input/output communication interface standard of PCIe channelwith NVMe protocol employed by the PCIe mode; the plurality of pins usedas the data line in the SD mode comprise pins of pin numbers 1, 7, 8,and
 9. 6. The method of claim 5, further comprising: using theelectronic device in the Linkup state of the PCIe mode to communicatewith the SD memory card device based on a communication connectionprotocol; operating the SD memory card device under the PCIe mode if thecommunication connection protocol succeeds; and sending a command CMD0corresponding to the SD mode at the pin CMD employed by the SD mode orsending the specific clock SDCLK corresponding to the SD mode at the pinCLK employed by the SD mode from the electronic device to the SD memorycard device via the first external signal port and the second externalsignal port, to control and make the SD memory card device enter the SDmode from the Linkup state if the communication connection protocolfails.
 7. The method of claim 6, further comprising: in the Linkup stateof the PCIe mode, disabling the second power signal of the PCIe modefrom the electronic device via the first external signal port and thesecond external signal port, to control the SD memory card device goback to the initial state from the Linkup state.
 8. An electronic deviceto be coupled to an SD memory card device and capable of controlling adata transmission mode of the SD memory card device, the electronicdevice to be at a host and having a first external signal port, the SDmemory card device at least can operate under an SD mode and have asecond external signal port, and the electronic device comprises: thefirst external signal port, having a plurality of pins to be coupled tomultiple pins of the second external signal port of the SD memory carddevice; a driving circuit, coupled to the first external signal port;and a processor, coupled to the driving circuit, configured for:controlling the driving circuit to send a first power signalcorresponding to the SD mode from the electronic device to the SD memorycard device through the first external signal port and a pin VDD1 of thesecond external signal port, to control and make the SD memory carddevice enter an initial state; controlling the driving circuit to send acommand CMD0 corresponding to the SD mode from the electronic device tothe SD memory card device through the pin CMD employed by the SD mode orto send a specific clock SDCLK corresponding to the SD mode from theelectronic device to the SD memory card device through a pin CLKemployed by the SD mode, to control and make the SD memory card deviceenter the SD mode from the initial state and operate under the SD mode;controlling the driving circuit to send a command CMD8 from theelectronic device to the SD memory card device through the pin CMD toquery whether the SD memory card device supports a PCIe mode;controlling the SD memory card device to operate under the SD mode ifthe SD memory card device responses that the PCIe mode is not supported;and sending a second power signal from the electronic device to the SDmemory card device via one of a pin VDD2 and a pin VDD3 of the secondexternal signal port if the SD memory card device responses that thePCIe mode is supported, to control and make the SD memory card deviceenter a Linkup state of the PCIe mode, a voltage level of the secondpower signal being lower than a voltage level of the first power signal;wherein a plurality of pins of an UHS-I input/output communicationinterface standard employed by the SD mode of the SD memory card device,used for a data line, are shared to be used by another input/outputcommunication interface standard of PCIe channel with NVMe protocolemployed by the PCIe mode; the plurality of pins used as the data linein the SD mode comprise pins of pin numbers 1, 7, 8, and
 9. 9. Theelectronic device of claim 8, wherein the processor is used to controlthe driving circuit to: communicate with the SD memory card device basedon a communication connection protocol in the Linkup state of the PCIemode; operating the SD memory card device under the PCIe mode if thecommunication connection protocol succeeds; and sending a command CMD0corresponding to the SD mode at the pin CMD employed by the SD mode orsending the specific clock SDCLK corresponding to the SD mode at the pinCLK employed by the SD mode from the electronic device to the SD memorycard device via the first external signal port and the second externalsignal port, to control and make the SD memory card device enter the SDmode from the Linkup state if the communication connection protocolfails.
 10. The electronic device of claim 9, wherein when the SD memorycard device is in the Linkup state of the PCIe mode, the processor isused to control the driving circuit to disable the second power signalof the PCIe mode from the electronic device via the first externalsignal port and the second external signal port, to control the SDmemory card device go back to the initial state from the Linkup state.11. A method used in an SD memory card device, an electronic device usedas a host having a first external signal port, the SD memory card devicecan at least operate under an SD mode and have a second external signalport, the SD memory card device to be coupled to the electronic devicethrough the first external signal port and the second external signalport, and the method comprises: receiving a first power signalcorresponding to the SD mode from the electronic device through thefirst external signal port and a pin VDD1 of the second external signalport, to control and make the SD memory card device enter an initialstate; receiving a second power signal from the electronic devicethrough one among a pin VDD2 and a pin VDD3 of the second externalsignal port, a voltage level of the second power signal being lower thana voltage level of the first power signal; communicating with theelectronic device based on a communication connection protocol in theLinkup state of the PCIe mode; operating the SD memory card device underthe PCIe mode if the communication connection protocol succeeds; andsending a command CMD0 corresponding to the SD mode at a pin CMDemployed by the SD mode or sending a specific clock SDCLK correspondingto the SD mode at a pin CLK employed by the SD mode from the electronicdevice to the SD memory card device via the first external signal portand the second external signal port, to control and make the SD memorycard device enter the SD mode from the Linkup state if the communicationconnection protocol fails; wherein a plurality of pins of an UHS-Iinput/output communication interface standard employed by the SD mode ofthe SD memory card device, used for a data line, are shared to be usedby another input/output communication interface standard of PCIe channelwith NVMe protocol employed by the PCIe mode; the plurality of pins usedas the data line in the SD mode comprise pins of pin numbers 1, 7, 8,and
 9. 12. The method of claim 11, further comprising: in the Linkupstate of the PCIe mode, controlling the SD memory card device go back tothe initial state from the Linkup state when it is from the electronicdevice through the first external signal port and the second externalsignal port to detect that the second power signal of the PCIe mode isdisabled.
 13. A flash memory controller of an SD memory card device, theSD memory card device to be coupled to an electronic device, theelectronic device to be at a host and having a first external signalport, the SD memory card device at least can operate under an SD modeand have a second external signal port, the second external signal porthaving multiple pins to be coupled multiple pins of the first externalsignal port of the electronic device, the SD memory card device furthercomprising a flash memory, the flash memory controller to be coupledbetween the flash memory and the second external signal port andcomprises: a register, configured for temporarily storing information ofthe flash memory; and a processing circuit, coupled to the register,configured for: receiving a first power signal, corresponding to the SDmode, sent from the electronic device through the first external signalport and a pin VDD1 of the second external signal port, to control andmake the SD memory card device enter an initial state; receiving asecond power signal sent from the electronic device through one among apin VDD2 and a pin VDD3 of the second external signal port, to controland make the SD memory card device enter a Linkup state of a PCIe mode,a voltage level of the second power signal being lower than a voltagelevel of the first power signal; communicating with the electronicdevice based on a communication connection protocol in the Linkup stateof the PCIe mode; controlling the processing circuit operate under thePCIe mode if the communication connection protocol succeeds; andreceiving a command CMD0 corresponding to the SD mode at a pin CMDemployed by the SD mode or receiving a specific clock SDCLKcorresponding to the SD mode at a pin CLK employed by the SD modethrough the first external signal port and the second external signalport, to control and make the SD memory card device enter the SD modefrom the Linkup state if the communication connection protocol fails;wherein a plurality of pins, used for a data line, of an UHS-Iinput/output communication interface standard employed by the SD mode ofthe SD memory card device are shared to be used by another input/outputcommunication interface standard of a PCIe channel with an NVMe protocolemployed by the PCIe mode; the plurality of pins used as the data linein the SD mode comprise pins of pin numbers 1, 7, 8, and
 9. 14. Theflash memory controller of claim 13, wherein when the SD memory carddevice is at the Linkup state of the PCIe mode, the processing circuitcontrols the SD memory card device go back to the initial state from theLinkup state when the processing circuit detects that the second powersignal of the PCIe mode is disabled.
 15. A method used in an SD memorycard device, an electronic device used as a host having a first externalsignal port, the SD memory card device at least can operate under an SDmode and have a second external signal port, the SD memory card deviceto be coupled to the electronic device through the first external signalport and the second external signal port, and the method comprises:receiving a first power signal, corresponding to the SD mode, sent fromthe electronic device through the first external signal port and a pinVDD1 of the second external signal port, to make the SD memory carddevice enter an initial state; receiving a command CMD0, correspondingto the SD mode, sent from a pin CMD employed by the SD mode from theelectronic device or a specific clock SDCLK, corresponding to the SDmode, sent from a pin CLK employed by the SD mode from the electronicdevice, to make the SD memory card device enter the SD mode from theinitial state and operate under the SD mode; receiving a command CMD8sent from the electronic device through the pin CMD wherein the commandCMD8 is used to query whether the SD memory card device supports a PCIemode; responding the electronic device that the SD memory card devicedoes not support the PCIe mode and maintain at the SD mode if the PCIemode is not supported; and responding the electronic device that the SDmemory card device supports the PCIe mode if the PCIe mode is supported,and then receiving a second power signal sent from the electronic devicethrough one among a pin VDD2 and a pin VDD3 of the second externalsignal port, to make the SD memory card device enter a Linkup state ofthe PCIe mode, a voltage level of the second power signal being lowerthan a voltage level of the first power signal; wherein a plurality ofpins, used for a data line, of an UHS-I input/output communicationinterface standard employed by the SD mode of the SD memory card deviceare shared to be used by another input/output communication interfacestandard of a PCIe channel with an NVMe protocol employed by the PCIemode; the plurality of pins used as the data line in the SD modecomprise pins of pin numbers 1, 7, 8, and
 9. 16. The method of claim 15,further comprising: communicating with the electronic device based on acommunication connection protocol in the Linkup state of the PCIe mode;operating under the PCIe mode if the communication connection protocolsucceeds; and receiving the command CMD0, corresponding to the SD mode,sent from the pin CMD employed by the SD mode or the specific clockSDCLK, corresponding to the SD mode, sent from the pin CLK employed bythe SD mode, from the electronic device through the first externalsignal port and the second external signal port to make the SD memorycard device enter the SD mode from the Linkup state if the communicationconnection protocol fails.
 17. The method of claim 16, furthercomprising: in the Linkup state of the PCIe mode, controlling the SDmemory card device go back to the initial state from the Linkup statewhen detecting that the second power signal of the PCIe mode isdisabled.
 18. A flash memory controller of an SD memory card device, theSD memory card device to be coupled to an electronic device, theelectronic device to be at a host and having a first external signalport, the SD memory card device at least can operate under an SD modeand have a second external signal port, the second external signal porthaving multiple pins to be coupled to multiple pins of the firstexternal signal port of the electronic device, the SD memory card devicefurther having a flash memory, the flash memory controller being coupledbetween the flash memory and the second external signal port andcomprises: a register, used for temporarily storing information of theflash memory; and a processing circuit, coupled to the register, usedfor: receiving a first power signal, corresponding to the SD mode, sentfrom the first external signal port and a pin VDD1 of the secondexternal signal port from the electronic device, to control and make theSD memory card device enter an initial state; receiving a command CMD0,corresponding to the SD mode, through the pin CMD employed by the SDmode sent from the electronic device or a specific clock SDCLK,corresponding to the SD mode, through a pin CLK employed by the SD modesent from the electronic device, to control and make the SD memory carddevice enter the SD mode from the initial state and operated under theSD mode; receiving a command CMD8 through the pin CMD sent from theelectronic device, the command CMD8 being used for querying whether theSD memory card device supports a PCIe mode; using the processing circuitto respond the electronic device that the secure digital memory carddevice does not support the PCIe mode and maintaining the SD memory carddevice at the SD mode if the SD memory card device does not support thePCIe mode; and using the processing circuit to respond the electronicdevice that the SD memory card device supports the PCIe mode and thenreceiving a second power signal through one among a pin VDD2 and a pinVDD3 of the second external signal port sent from the electronic deviceif the SD memory card device supports the PCIe mode, to control and makethe SD memory card device enter a Linkup state of the PCIe mode, avoltage level of the second power signal being lower than a voltagelevel of the first power signal; wherein a plurality of pins, used for adata line, of an UHS-I input/output communication interface standardemployed by the SD mode of the SD memory card device are shared to beused by another input/output communication interface standard of a PCIechannel with an NVMe protocol employed by the PCIe mode, and theplurality of pins of the UHS-I input/output communication interfacestandard employed by the SD mode comprise pins of pin numbers 1, 7, 8,and
 9. 19. The flash memory controller of claim 18, wherein theprocessing circuit is used for: communicating with the electronic devicebased on a communication connection protocol in the Linkup state of thePCIe mode; controlling the SD memory card device operate under the PCIemode if the communication connection protocol succeeds; and receivingthe command CMD0, corresponding to the SD mode, at the pin CMD employedby the SD mode or the specific clock SDCLK, corresponding to the SDmode, at the pin CLK employed by the SD mode through the first externalsignal port and the second external signal port if the communicationconnection protocol fails, to control and make the SD memory card enterthe SD mode from the Linkup state.
 20. The flash memory controller ofclaim 19, wherein when the SD memory card device is in the Linkup stateof the PCIe mode, the processing circuit is used to control the SDmemory card device go back to the initial state from the Linkup state ifthe processing circuit detects that the second power signal of the PCIemode is disabled.